The invention relates to an aluminum casting alloy for casting operations, in particular die-casting operations. Further the invention relates to the application of the aluminum casting alloy in particular into cast products for automotive components.
Conventional aluminum casting alloys have many attractive properties, such as high ultimate tensile strength ( greater than 180 MPa) and high elongation at fracture ( greater than 9%) with moderate 0.2% yield strength ( greater than 120 MPa). However, there is a demand for aluminum casting alloys for manufacturing cast product which combine improved mechanical properties, in particular high elongation at fracture, with a good corrosion resistance, such as resistance to pitting.
Some disclosures of aluminum casting alloys found in the prior art literature will be mentioned below.
EP-A-0918095 discloses a structural component made of an aluminum die-casting alloy, consisting of, in weight percent:
By the addition of the very expensive Sc in a range of 0.05 to 0.4% and optionally in combination with Zr in a range of 0.1 to 0.4% and the requirement of an heat treatment in the range of 230 to 350xc2x0 C. following the die-casting of the structural component a yield strength of about 120 MPa, a tensile strength of 180 MPa and an elongation at fracture of 16% is obtained.
EP-A-0918096 discloses a structural component made of an aluminum die-casting alloy, consisting of, in weight percent:
By the addition of the expensive V in a range of 0.05 to 0.3 and the requirement of an heat treatment in the range of 200 to 400xc2x0 C. following the die-casting of the structural component an yield strength of above 120 MPa, a tensile strength of more than 180 MPa and an elongation at fracture of more than 10% is obtained.
EP-A-0908527 discloses an aluminum casting alloy, in particular suitable as a die-casting alloy, consisting of, in weight percent:
This casting alloy is capable of achieving a yield strength of more than 100 MPa and an elongation of more than 14%. Further the die-sticking of the alloy in a die-casting operation can be reduced by replacing part of the Mn by more expensive Ce.
WO-A-00/17410 discloses an aluminum die-casting alloy, consisting of, in weight percent:
This aluminum die-casting alloy does not suffer from die-sticking and cast products are capable of achieving a yield strength of at least 117 MPa and an elongation of at least 18%.
U.S. Pat. No. 4,605,448 discloses an aluminum wrought alloy for use in manufacturing both can body parts and can ends, the aluminum wrought alloy having a composition, in weight percent:
Can stock material and which is being rolled and otherwise thermo-mechanically treated is not within the technical field of the present invention.
It is an object of this invention to provide an aluminum casting alloy that can be used in a variety of casting operations.
It is another object of this invention to provide an aluminum casting alloy ideally suited for use in die-casting operations, in particular in high-pressure die casting operations.
It is also an object of this invention to provide improved cast products and components manufactured from an improved aluminum casting alloy cast members that ideally are suited for automotive applications.
It is also an object of this invention to provide an aluminum casting alloy for making cast products having in at least the as-cast condition the following minimum mechanical properties: 0.2% yield strength (YS) of at least 120 MPa, a tensile strength (UTS) of at least 180 MPa and an elongation at fracture of at least 9%.
It is also an object of this invention to provide an aluminum casting alloy for making cast products having in the as-cast condition the following minimum mechanical properties: 0.2% yield strength of at least 120 MPa, a tensile strength of at least 180 MPa and an elongation at fracture of at least 9%, which minimum mechanical properties can be achieved without the addition of expensive alloying elements such as Sc, V and Ce.